Characterization at Rest and During Adenosine Infusion

Renal function is known to be a strong predictor of cardiovas- cular prognosis, and cardiorenal disease is increasingly in- vestigated in medical research. In this study, we tested the hypothesis that a single combined cardiorenal scintigraphy ex- amination with the perfusion tracer 99m Tc-tetrofosmin is feasible and may allow the simultaneous investigation of cardiac and re- nal pathology in cardiovascular patients. Methods: Thirty pa- tients scheduled for dual-day gated SPECT also gave their informed consent for a renal acquisition after a single injection of 370 MBq of 99mTc-tetrofosmin, at rest (30 patients) or with adenosine (21 patients), and to undergo an additional standard renal study with the glomerular tracer 99mTc-diethylenetriamine- pentaaceticacid(DTPA)(74MBq)after1wk(24patients).Kidney images and renograms were obtained. Renal uptake index, expressed as the percentage ratio of kidney counts cumulated over the second minute after injection to the administered dose, was calculated as a functional renal parameter. Time to peakactivityandseparatekidneypercentage uptake(astheper- centage contribution of each kidney to total renal uptake) were also calculated. Results: Compared with 99m Tc-DTPA, 99m Tc- tetrofosmin provided better-quality kidney images, with a higher uptake index (13.17% 6 4.76% vs. 8.33% 6 2.45%, P , 0.001) and with comparable separate kidney percentage uptake and times to peak activity. 99m Tc-tetrofosmin uptake index was sig- nificantly lower in the patients who were more compromised according to renal and cardiovascular functional parameters, and correlated with 99m Tc-DTPA uptake index (r 5 0.77, P , 0.001), serum creatinine (r 5 0.59, P , 0.005), log brain natriu- reticpeptideN-terminallevels(r 52 0.65,P ,0.005),myocardial and carotid intima-media wall thickness (for both,r 52 0.61,P , 0.005), and the Doppler index of renal vascular resistance (r 5 20.60, P , 0.005). In the 21 patients who underwent the provoc- ative test, adenosine induced a significant decrease in renal 99mTc-tetrofosmin uptake index (from 14.12% 6 4.50% to 11.81% 6 3.33%, P , 0.005) suggesting a decrement in renal perfusion or function. Conclusion: 99mTc-tetrofosmin cardiore- nal scintigraphy is feasible at low cost as a single-shot study andmayallow boththeevaluation ofrenal morphology andreno- grams during a cardiac study and the calculation of renal func- tional parameters.